If you are looking for an email and it is tricky to find, Gmail has a search box above your emails to make things easier.

You can search for the sender or you can search for what the email was about (e.g. ice skating) or the subject.

When you start to type in the search box, Google will offer you some suggestions like 'only emails with attachments' or 'from the last 7 days' these help you get better results.